High tension dry contact rectifier apparatus



April 1942- H. J. F. ALRIQ 2,279,101

HIGH TENSION DRY CONTACT RECTIFIER APPARATUS Filed Dec. 14, 1939 3Sheets-Sheet 1 A ril 7, 1942. H. J. F. ALRIQ 2,279,101

HIGH TENSION DRY CONTACT RECTIFIER APPARATUS Filed D60. 14, 1939' 3Sheets-Sheet 2 -April 2' H. J. F. ALRIQ 2,279,101

HIGH TENSION DRY CONTACT RECTIFIER APPARATUS Filed Dec. 14, 1939 3Sheets-Sheet 3 UUUUUUUUUUUUU Patented Apr. 7, 1942 l HIGH TENSION DRY'coN'rAor RECTIFIER APPARATUS Hubert Jean Francois Alriq, Paris, France,

signor, bymesne assignments, to, The Union Switch & Signal Companyr SWssvale, Pa, a, corporation of Pennsylvania Application December 14,1939, Serial No. 309,214

In Erance July. 27, 1939 4 cla ms. (c1. 115-365 This invention relatesto apparatus for obtaining, from a, source of alternating electriccurrent, high uni-directional: or direct current potentials by' means ofrectifiers of the dry contact type such, for example, as copper oxide orselenium rectifiers; and has for its object to provide improvedapparatus of' this character.

Although theoretically it is possible, byproviding the required numberof rectifier elements connected in series with one another to obtain anydesired uni-directional or direct currentpoe tential, it is. founddiflicult inpractice to ensure that the rectifier elements shallwithstand the very high potentials involved while beingeiTecti-velyinsulated and cooled, and the invention enables thesedimculties tobe effectively overcome.

According to one feature of the invention, the seriesconnectedrectifying elements are arranged in groups in a hollow container, thewalls of which are constructed of insulating material, and whichcontains, a bath of highly insulating fluid inwhich the elements areimmersed, the elements being so arranged that the portions thereofadjacent to one another are as nearly as pos sible at the same electricpotential.

According to another feature of the invention, the apparatus constructedas above described is provided with a cooling device of the circulatingliquid type, this device being arranged adjacent to the low potentialend of the rectifier series of groups, and is electrically connected tothe corresponding terminal whichis earthed.

In a modification of the arrangement above referred to, in which thecooling fluid employed in the cooling device is a good insulator such asoil, the inlet and outlet pipes for this fluid being constructed ofinsulating material so that the body of the cooling device is insulatedfrom earth, the device is electrically connected as, in the previousarrangement to the low: potential terminal of the rectifier circuit,this terminal being, however, at a potential which is different fromearth and this difference of potential beingtion of; the portion of:apparatus; constructed in.v

accordance with the invention containing the rectifier groups, Figure 2;being a. similar. view of the cooling device.

Figure 3; is a, similar View of the complete ap-, paratus showing thearrangement. of the'rectifier portion, the cooling: device. and otherparts of the ppara u Figures 4, 5 and 6f areviews, of one form of. theautomatic cut-out. device above referred to, Figures 4 and 5 being viws, thereof. in longitudinal section and end elevation respectively,while Figure 6 is, a view similar to, Figure 4, showing the device underdifferent conditions of operation- Referring now to, Figure 1, it willbe seen thatthe rectifier elements of the apparatus are arranged inbanks l superposed one aboveanother: in a vertical column withina casing2, the. walls of which are constructed of electrically insulatingmaterial, the banks I, being supported on suitable vertical standards 3mounted upon thebase 4 ofthe casing 2.

Each of the banks I comprises a number of groups. 5 of rectifierelements arranged in two superposed rows, or layers and .it. will .benoted that groups are so, arranged in the bank that the groups in theupper and lower row at. one end of the bank which are at substantiallythe same potential are more closely spaced vertically than the groups atthe opposite end: ofthe bank which are at considerably diiierentvpotentials. Furthermore, the, group of elements at one end of the upperrow in one bank is more closely ada. jacent to the opposite group at theend of the lower row in the next bank above than'are the correspondinggroups at the other ends, ofthe two ba ks.

It will be understood that the rectifier elements of the groups areconnected in series with one another, either directly orin the mannerusually adopted for the so-called voltage doubler systems and fromthearrangement above described it will .be seen that in general theseparation ofthe groups in the rows of each bank and in the adjacentrows of groups in adjacent banks is such that the greater the differenceof potential between two groups, the greater is the distance by whichthey are separated from one, another.

The casing l. is filled withan insulating liquid in which the groups ofrectifier elements are submerged and a cooling device'shown Figure 2 isprovided at the upper end of the casing i,

Referring now to Figure 2, it will be seen that the cooling devicecomprises a head orupper casing 6 fitted on to the upper end of thecasing 2. The casing 6 which is preferably constructed of metal isprovided with suitable packing for preventing leakage of the insulatingliquid which fills the whole space within the casings 2 and 6. Thisliquid is maintained under a suitable hydraulic head or pressure bymeans of the vertical pipe 1, the upper end of which terminates anexpansion chamber 8.

Mounted within the casing 6 is a tubular cooling coil 9 preferablyconstructed of metal and provided with an inlet pipe I0, and outlet pipeI I and an overflow device I2 of any suitable type, the coil 9 beingthereby supplied with a suitable cooling liquid preferably water, thecirculation of the liquid through the coil 9 being "effected by asuitable pump or otherwise.

The complete apparatus is shown diagrammatically in Figure 3, and itwill be seen that the casing 2 is shown as containing, in addition totherectifier groups 'I, a condenser l3 (in the case of voltage doublerapparatus) and the transformer l4 through which the rectifier-system issupplied with current the transformer l4 being mounted upon a platformIS in the casing 2 and projecting within the upper casing 6.

The casing 2 is shown as mounted upon a pedestal or base member IS inwhich is mounted an insulating sleeve or bushing I! for the highpotential conductor l8 of the rectifier circuit, the low potentialterminal'of this circuit as well as the corresponding terminal l9 of thetransformer l4 beingconnected to the inlet and outlet. pipes III, II ofthe cooling coil 9 by low resistance conductors 20, 2|. The conductors20, 2| may be connected to earth at E through a conductor 22.

of the bulb and connected to flexible external conductors 35, 3B. Theconductors 35, 36, are connected either in the supply circuit of theprimary or low tension winding of the transformer l4 or in the operatingcircuit of a suitable contactor device controlling this transformercircuit, the operation of the safety device being as 7 follows:

' of the magnet 30 and the magnetisable piston With this system ofconnection, it will be understood that the terminals of the rectifiercircuit arethe conductor 18 and the earthed conductor 22.

In a modified system of connection, however, in which the pipes II), IIare constructed of insulating material and the cooling liquid suppliedto the coil 9 is also a relatively high insulator, the terminalconductor 22 may be-arranged to be at a potential different from earth,so that the circuitindicated in dotted lines at 23 will be traversed bya" corresponding current and may be constituted by any desired apparatusor device which is required to be operated by unidirectional currentother. than that to which the high voltage terminals 18' and 22 areconnected.

Referring now to Figures 4, 5 and 6, a safety device is illustratedcomprising a tubular-member 24 preferably constructed of non-magneticmetal and interposed in the inlet pipe I0 through which cooling liquidis supplied to the cooling coil 9 shown in Figures2 and 3. i

Loosely mounted upon a suitable guide rod 25 axially arranged within themember 24 is a small piston 26 constructed of magnetisable material, acontrol spring 21 being interposed between the inner end of the piston26 and the inner end of a hollow plug 28 fitted into the outletend ofthe member 24. I

1 Mounted in suitable trunnions or bearings as indicated at 29' is apermanent magnet 30, the arms 3| of which embrace the central portion ofthe tubular member 24 so as to' be adjacent to the piston 26. i g

. A bracket 32 is secured to the magnet 30 and carries a mercury switch33 of the well known type comprising a bulb containing a body of mercury34 and conductors sealed into the wall 26,under these conditionsmaintains the magnet 30 in its deflected or operative position in whichthe mercury switch 33 is in such a position that the body of mercury 34electrically connects the conductors 35, 36, thereby closing the circuitof the primarywinding of the transformer l4 or causing this circuit tobe closed through the contactor device above referred to.

The rectifier apparatus is accordingly rendered operative as will beapparent without further explanation.

In the event, however, of the flow or circulation of cooling fluid inthe cooler coil 9 failing for any reason, the cessation or substantialreduction of the flow of cooling liquid through the tubular member 24will permit the spring 21 to displace the piston 26 to its inoperativeposition shown in Figure .4. The magnet 30 is'correspondinglydisplaced,carrying with it the mercury switch 33 so that the body of mercury 34(as shown in Figure 4) no longer eflects electrical connection betweenthe conductors 35, 36.

The supply of alternating currentto the primary winding of thetransformer 14 is thus interrupted either directly orthrough thecontactor device, and the rectifier apparatus is thus ren deredinoperative until the circulation of cooling fluid is restored. Damageto therectifler apparatus, owing to failure of the cooling ystem, isthus automatically prevented;

The invention'is evidently not limited to the particular arrangement andconstruction above described and illustrated by way of example, whichmay be varied in many respects without exceeding the scope of theinvention.

The casing 2, for'example, may be arranged also to contain any otheraccessory apparatus or devices other than those above described and thecooling device which may be of any preferred type may be arranged withinthe casing in any manner adapted to ensure the effective circulation ofthe cooling fluid in which the rectifier and other element of theapparatus are iznmersed.

I claim:

1. In high tension rectifier apparatus in which.

rectifier elements of the dry contact type are immersed in a bath ofhighly insulating fluid within a hollow container in such manner thatthe portions of the individual rectifier elements adjacent to oneanother are as nearly as possible at the same potential and in whichthe. low potential terminal is insulated from earth, the combination ofa cooling device of the circulating liquid type disposed in said bathand having inlet and outlet pipes of insulating material and,

containing a' circulating liquid which is a good insulator, the body ofthe coolingdevice being connected to the low potential terminal of therectifying apparatus and the difference of potential between thisterminal and earth being utilized to supply unidirectional current foroperating any desired apparatus or device.

2. In high tension rectifier apparatus in which rectifier elements areimmersed in a bath of highly insulating material which is kept cool by acooling device of the circulating liquid type immersed in the bath, thecombination of a piston adapted to be displaced by the flow of coolingliquid, and switch means for controlling the supply of current to therectifying apparatus operatively connected with said piston.

3. In high tension rectifier apparatus in which rectifier elements areimmersed in a bath of highly insulating material which is kept cool by acooling device of the circulating liquid type immersed in the bath, thecombination of a safety device comprising a piston adapted to bedisplaced by the flow of cooling liquid, and when thus displaced toefiect the operation of a switch to close either directly or through acontactor device the circuit through which alternating current issupplied to the rectifying apparatus, the piston being biased toautomatically return to an initial position in which the supply ofcurrent is cut off in the event of failure in the flow of thecirculating cooling liquid;

i. In high tension rectifier apparatus in which rectifier elements areimmersed in a bath of highly insulating material which is kept cool by acooling device of the circulating liquid type immersed in the bath, thecombination of a safety device comprising a magnetizable piston adaptedto be displaced by the flow of cooling liquid, a permanent magnetdisposed to follow the movement of said piston, and a switch controllingthe supply of current to the rectifying apparatus operated by themovement of said permanent magnet.

I-IUBERT JEAN FRANCOIS ALRIQ.

